Protective appliance for electric circuits and apparatus.



No. 882,498. PATENTED MAR. l'7, 1908. H. H. HORNSBY & E. W. ANGER, JR.

PROTECTIVE APPLIANCB POR ELECTRIC CIRCUITS AND APPARATUS. APPLIOATION FILED M1019, 1901.

3 SHEETS-SHEET l.

PATENTED MAR. 1'7, 1908. H. HQHORNSBY Kn-E. W. ANGBR, IR. l PROTECTIVE APPLIANCE FCR ELECTRIC CIRCUITS AND APPARATUS.

l No. 882,498.

APPLICATION FILED DBC.19, 1901.

3 SHEETS-SHEET 2.

No. 882,498. PATENTED 17, 1908. H. H. HORNSBY da E. W. ANGER, JR. l PROTECTIVE APPL'IANCE POR ELECTRIC CIRCUITS AND APPARATUS.

. APPLICATIONPILED 11110.19. 1901.

3 SHEETS-SHEET 8.

HARRY E. IIoENsBY AND EDWARD w; ANGEE, JR.,'oECEIcAGo, ILLINOIS.

Y PROTECTIVE APPLIANCE Eon ELECTRIC CmCUITs AND APISAEATUS.

l Specification of Letters Patent.

Patented March 17, 1908.

Application filed December 19, 1901. Serial No. 86,506.

To all whom it may concern:

Be it known' that we, HARRY H. HoENsBY and EDWARD W. ANGEE, Jr., citizens of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a' certain new and useful Im rove- 4 ment in Protective Appliances for E ectric Circuitsv and Apparatus, ofA which the following is a full, clear, concise, and exact description, reference being had to the accompany- .i ing drawing, forming a-part of this specification.

Our lnvention relates to Improvements 1n4 f tion of the fuse wires or links within the tubes ed. The next step was to in'close the supplemental fuse-in the tubes, but here again the nfire was transmitted to the outside, to burn or sheaths.'

Owing to the danger of fire attending the use of the o en or uncovered fuse, it .was

sought to inc ose the fuses in tubes capable of withstanding the yeffects of the burnin and arcing at the fuse. Such inclosed fuses 4owever were objectionable as there was no visual indication of the destruction or blowing of the fuse. It was then tried to remedy this defect by providin a su plemental fuse alohg the outside of te inc osing fuse tube which in attempting to carry the current after the main fuse wire melted, would fuse and burnthe outside of the tube so as to discolor the same and thus enable the destroyed fusewire to be readily picked'out. But in thus ac uiring one advantage, the o`bject of the inc osing tube in preventing fire exterior thereto was to a large extent defeator discolor the tube, etc. ,4 thus losing in a large measure the advantage sought to be gained. I v

Itis one object of our invention to provide a device of the kind described in which all the fire due to the melting of the fuse shall be rertained within the inclosing fuse tube and one in which at the same time a signal, exterior of the tube, shall be given, thus deriving at onceall the advantages sought by reason of the inclosing of the fusewir'e or link and having none of the usual disadvantages on account of the exterior signal.

` A further object is to so construct the device that the fuse linkshall not be placed under a state of stress, whereby a rapid deterioration of the same is prevented and a long life thereof is secured..

Still other objects of our invention are to provide protective a pliances having signals to indicate the con ition of the fuse wires, where such appliances are intended for heavy current work and are necessarily of considerable initial cost. Such devices are provided with an outer casing ca able of withstanding the destructive forces ue to burning out of the fuse wire or link, and with an inner sheath for the fuse-wire whereby when theduse is destroyed the said sheath and the fuse wire may be replaced at small expense. Such devices, have not heretofore been provided with sifgnaling means to indicate the condition o the fuse and are therefore objectionable as noted above. Our linvention therefore, seeks to provide a means `for exteriorly indicating when-'the fuse within is disrupted, and to vprovide a device in which the same is accomplished without complication of parts, and- 1n an eflicient and inexpensive manner.

The invention also embraces special features of construction, all of which will be made clear in the description of the several embodiments thereof in the accompanying drawings, wherein the same reference letters are applied to like parts throughout, and in which:

Figure 1 is one form of the inclosed fuse or protective appliance of our invention; Figs.

,-2, 3, 4'and 'are detailviews of the parts thereof.. Fi 6 is a longitudinal section of the device o Fig. 1 and one form of its inclosing casing or tube. Fi 7 is a transverse section on line 7-7, Fig. 6; Fig. 8 is a similar view on line 8 8 Fig. 6; Fig. 9 is a transverse section on the line' 9 9 Fig. 6; Fig. 10 is a detail perspective view of the spring clip of the casing which `is adapted to receive the inner end of the fuse tube; Fig. l

1 1 is a view of a modified form of the end cap for the casing; Fig. 11HL shows a still dilierent form of end cap with its contact clip; Fig. 12 illustrates a modification of the contact clips for the outer or forward end of the fuse sheath the same being adapted for heavy Vcurrent work; Fig. 13 is a sectional view of a modified form of the inner or closed end ofthe sheath adapted for heavy current circuits; Fig. 14 is a sectional view ofthe opposite end of the same-also ada ted for hea currents; Fig. 15 is a sectiona view of a di ferent form of the closed end of the sheath 'washer 19 having a rectan with its casing; Fig. 16 shows the invention I different way of leading the conductors into the block; Fi 21 is a lan view of a cut out block of the ouble po e t 'e with the fuses in-place thereon; Fig. 22 s ows how the invention may be used in connection with a signaling system; Fig. 23 shows a modifica tion of the circuit closing springs of the sig' naling circuit.

Like letters indicate like the several views.

Referring to Figs. 1 to 5 the readily removable and replaceable inclosed fuse of our device comprises the insulating pipe, tube or sheath 2, having yat one end ametallic contact cap, 3, secured thereto by a prong or pin,

'4, andhaving a terminal rod, 5, of suitable material such as co per, riveted, soldered or otherwise secured tliereto and extendin into the sheath. Near the- 4other end o the sheath 2, is provided a metallic sleeve, 6, firmly aiiixed in position bymeans of a suitable prong or pin, 7'.' AAs shown in Figs. 1 and 2, the outer end of' this sleeve, 6 has a aring rectan ula'r end 8 in which a slot 9 is formed, Wit in the outer end of the sleeve,

6, a cu plunger or sleeve-like cap, 10 is` adapte to t, said cap being split or notched as at 11, Fig. 4, in the inner end tocause it to adhere to the interior of the sleeve,L 6, with a'slight spring pressure. While the inner end of the cap or plunger, 10, may beconstructed in any manner desired, weprefer to provide a separate, and` readily removable plug 12 having an enlar ed portion, 13, and asmaller portion 14., he end of the plu 12 opposite'the portion 14, is providedwit y a groove or grooves, and the end of the cap is crlmped as seen in Fig. 4, this crimped end engaging in the groove or grooves to firmly engage the plug, Without interfering Withits ready removal. This extended end 14, of the cap, as will hereafter be described, constltutes the indicating part of the protective device which is adapted to protrudeand when used in connectlon with a casing to ro- ]ect through an aperture in the same, W en the fuse 1s blown, melted, burned out or disrupted. A short pin, 15, on the cap 10, enters the. slot, 9, when the cap is in normal ositlon, to. prevent relative rotation, and a ong pin, 16, extends completely through the .8 of the sleeve, 6, is normally pressed against the pin 16 by a coil orother suitable spring, 18 which 1n turn bears against' a second lar openin just large enough to slip over t e end 8 of se' parts throughoutv jNearthe other end of the cas' At'allic contact sleeve 29, surroun said sleeve having the inturned sp con-' eve 6. These Washers and the spring may be all secured together and when in lace as shown in Fig. '1, the long Way of t e aperture in washer 19 is turned cross-wise of the end 8, so as to provide a bearing for the washer.

vThe fuse wire or line 20 extends between the terminal 5, and alike artv21 which is in electrical contact with tile contact sleeve, 6 as shown in Ei 6. -A small supplemental fuse or conducting wire, 22, extends between 'the terminal, 5, and the cap, 10, and is secured thereto in any desired manner so as to hold the cap, 10 in its inner position against the tension of the spring 18.

Under normal conditions the current flows between the end cap, 3, andthe sleeve,

6, which are suitably connected in the electrjc circuit and over thefuse wire or link 20.

On account of the resistance of the supplemental or' auxiliary and attenuated wire or fuse 22 and the poor contact made betweencap or plunger 10 and contact sleeve, 6, very little current normally flows over these parts.

But when a heavy current greater than the capacity of the fuse wire 20, passes over the circuit, thefuse-wire meltsand opens the circuit, and the current then iiows thro h A the supplemental fuse or wire 22 in s v cient quantity 'to immediately fuse, break or disrupt it, thus permitting spring, 18 which presses ainst washer, 17 and pin 16, to e'ect the indicator, 14..- It is thus a parent that the usual objectionable fire or outside of the tube is avoided.

A 'One form of inclosing casing with which the device is ada ted to be used yis shown in Figs. 6 to 10. ere a tube or casing, 25, of suitable insulating material is provided with a metallic end ca 26, threading thereon and having ,secured t ereto b screws 27 a split spring sleeve or termina cli 28, Fig. 10, which is adapted to receive t e endcontact or cap'3 of the inclosed fuse and owmg to the extended surface and spring ,pressure )to make good electrical contact therewith.

, 25, a mekan aperture alining with the indicatplunger 14 of the fuse tube. Under norm condltions, when the inner tube or fuseis in the same,

the osition shown in Fig. 1 the indicator stan so that its end does not pro'ect bepend the end of the casing, but 'w en'the ewire is blown, the indicator is forced out and 1s 'thus exposed. The word' blown may if desired be placed upon the indicator,

as shown, so as tobe out of sight normally iso l seen to be slight, as the lused as beforeand the cap and exposed only when the fuse wire is disrupted. The enlarged part 13 of the indicator engages the inside of the cap 31, to pre" vent the loss of the cap ,or plunger 10.

In order to insure the ready insertion of the end, 3, ofthe fuse sheath the spring clip, 28, the guiding member, 32, preferably of insulating material, is -fixedly held in the tube, 25, by suitable means and is provided with a central Haring or funnel sha e bore by means of which the said fuse sheat is guided into placewhen` being inserted, this action being assisted by the flaring mouth of the clip 28 itself. It will be understood that the casing is adapted to be connected in the electric circult by suitable terminal vclips engaging the metallic-end or contact cap, 26 and contact sleeve 29. To replace a fuse after being blown, it is merely necessary to remove the cap, 31, and to withdraw the sheath 2, the latter being easily grasped yby the rectangular end 8 thereof. AA new tube or sheath 2 is then inserted, the same washers and spring, as well as indicator being 31, is replaced. The costl of replacing the' b arts necessary to be changed are comparatlvely inexpensive. All danger of fire is avoided as everything is kept inside and moreoverV an exterior signal is obtained. l

Fig. 13 shows the closed end of the tube for heavy current. The tube 2 is pinned to the heavy metallic cap 35 which has an in ternal groovel 36 into which a sheet metal p shell is pressed or spun, the terminal 38, being provided with outwardl extending ends, 38, locatedbetween and eld by the shell 37 and cap, 35, whereby a firm mechanical connection and a good electrical contact with the metallic end of the tube is secured. The part extending into theH tube maybe cony veniently formed into a loop as shown in any desired manner.

Fig. 14 shows the other end of the tubev though other constructions and arrangements may be employed. The fuse wire or link maythenbe secured to the terminal 38 for heavy work. Here the terminal, 39 to which the main fuse 2O is `connected is in loop or' staple form with its ends riveted, soldered or otherwise suitably secured to the heavy metallic contact sleeve 40.

Fig.,15 shows an arrangement of the lclosed ends of the casing and the fuse tube or sheath for extremely heav current work. The tube 25 is inclosed y the contact cap, 26 which carries as before the split spring end clip 28. The fuse sheath carries the heavy metallic end piece, 41 as shown. Alinin apertures are provided through caps, 26 an 41 and a screw 42 passes through the outer end into the inner cap, whereby the latter is mechanically and electricall connected with the former. The rod, 5 to w ichrthe fuse wire own fuses is thus the cap may be upset thereinto as shown In Fig. 11 the cap 26 o'f the casing is provided with clips, 26, cast integrally therewith and adapted to receive screws to secure them in position to the circuit terminals.

In Fig. 16, the invention is shown applied'` to the plug type of fuse. This comprises the insulatlng cap or casing 45 having the usual central aperture 46 and carrying the threaded shell 47 forming one terminal of the device. A similar insulating end wall or piece, 48 is provided at. the other`end through a central aperture in which the inclosed end of the fuse tube or sheath projects and is ada ted to connect with a contact of a suita le socket. The contact sleeve, 6 of the fuse cartridge is engaged by a spring contact clip, 49 to complete the circuit to the shell 47, which in turn contacts suitably inthe socket in which the plu is inserted. Otherwise the construction is t e same as in Fig. 1, except that'the indicator is made small enough for the usual aperture 46 of the plu(T cap. The o eration is the same `as 4before describedso t at when the fuse wire is disrupted the, spring 18 forces the indicating end of the` p unger 14 out of the hole in 'the cap, the part, 13, thereof serving to retain the plunger within the cap.v A pin 50 andcorresponding bayonet slot in the clip 49 are provided to prevent forcing the fuse tube out of place when the end 3 is pressed against its contact.

Fig. 17 shows a modification of the arrangement of the ap liance in that the fuse wire or link 20' is itse f attached to the Spring plunger 10; it is obvious that this form is within the scope of certain phases of our invention. When the fusev wire is `disrupted the plunger indicator is ejected by the spring and makes known the fact. Again, the sul plemental fuse or conducting wire previous y ldescribed may be replaced by meansof other attenuated, fragile or threadlike mechanical restraining means, which is ruptured, destroyed or burned out by the blowing-of the fuse wire to cause the same to releasethe indicator and which .disruption doesnot Idepend upon the heating or fusing action of the electric circuit upon the said retaining means. One such arrangement is shown in Fig. 18 wherein 20 is thev main fuse and 55 is the thread-like or other attenuated indicator retaining means.l When the fuse wire'blows,

,the said means is burned up by the heat and fire of the fusing of the fuse wire whereby it is caused to release the indicator y and the same is actuated by its spring. Other forms and other'methods all within the spirit of our invention are apparent, but those described aredeemed sufficient for purposes ofillustration..

Fig. 19 shows a different form of casing. A base, 60 of porcelain, lass or other suitable substance, is provi ed with terminal clips, 61 and 62 of any desired construction and are connected with suitable conductors 63 and 64. A fuse like that of Fig. 1 is adapted to be held in said terminals and the whole is covered by a cover or casing 65 held in place by suitable screws, 66, 66. A cap, 67 is threaded upon said casing and has an aperture through which the indicator projects when the fuse wire is blown. A steering means is also provided consisting of charin eled projections 68 and 69 formed respectively upon the base and cover, and having aliiaring opening to better guide thev fuse in p ace.

Fig. 20 shows a similar arrangement exl. cept that the conductors 64 and 65 are led through upwardly sloping apertures into the block, whereby rain and moisture cannot penetrate to the interior 'of the same.

Fig. 11" shows a modification of the contact and terminal `clips adapted to be used in the device of Figs. 19 and 20. The contact band, 3, on the sheath has a longitudinally extending flat clip 3 adapted to be inserted in a slot in the perpendicular terminal clip 62, a screw being passed through both the upper flexible art of said clip and the contact clip 3a an then thread' into the said terminal clip. A hole would e provided in the`casing 65 to permit the insertion of a screw driver. Similar clips could; beprovided for theuse tube at its lower contacts, but it is not necessary to show the same.

Fig. 21 shows a cut-out block provided :with fuses of our invention, the terminal y the sign extension of the block having grooves in its u per surface for the conductors 71 and .72 W ch are connected by means of suitable permanent connections on the block with the contact clips adapted to receive the fuses 73 and 74. f

Fig. 22 shows a signaling system for these devices. It is customary to mount them upon switchboards and it is convenient that the operation of any'fuse in a group or upon a articular board should operate a si e accordingly rovide Aa lamp 75 or a bell 76 either of whic may be used as a signal as desired, the circuit for which signal is closed by means of any fuse of a group such as is typilied by fuse 77. When the indicator drops r is forced from the lower vend of the casin 77, the contacts 'Z8 and 79 are closed toget er and the circuit of the lamp isl closed. Any s stem of wiring of course may be employe a signal for each group or for as many groups as desired being provided.

Fig. 23 shows a different way of connecting al circuit contacts, that is, by a metallic end'or band for the indicator and two sprin s between which it crowds. This ha's the a vantage of clinging or sticking in Ato receive said terminals and arr place by the rictional contact of the plunger and springs to maintain the signal circuit l close From the foregoing it' will be apparent that the fuse tube may be used alone 1n cer- -tain relations, and that it is capable of use stitutions may be made in our device with.

out departing from the principle of the same, and we therefore hold it to include all such variations as fairly fall within its sco Having described our invention w at We claim as new and desire to secure by Letters Patent is: 1. In a protective appliance for electric circuits and apparatus, the combination with an insulating sheath, of a fuse wire within the sheath, suitable terminals mounted u on said Vsheath and electrically connected with the said fuse Wire, stationary contacts ed to include the said appliance in an electric circuit,

with an inclose sheath of insulating material," of circuit terminals mpuntedupon the exterior of said sheath in proximity to the' ends thereof, stationary contact devices to 4receive said terminals and connect the'ap li# ance in the electric circuit tobe rotecte a fuse wirejwithin the sheat'h and'in electrical connection with said terminals, and' a sp normally held in nonindicating position a ainst the tension of the spring and e'ected W en the fuse Wire is disrupted, said-p unger being free from the external conductors of the electric circuit so as not to be im ded thereby, in'its movement, substanti y as described.

- 3. In a protective appliance for electric circuits and ap aratus, the combination with aninclosed) fuse tube. of insulating material, of metallic circuit terminals mounted upon the exterior of said tube, stationary contacts to receive said terminals-and adapted to' connect the'appli'anc-e in the electric circuit to be u the tube and e ectrically connected with said terminals, a spri plunger located in the end of the tube an secured to o'xie end ofthe fuse wire, and normally held thereby against rotected, -a fuse wire within isb 1111 11o plunger located in the end.of the Asheat .v

y 5 of the fuse, substantially as described.

4. The combination with a sheath having terminals carried thereon, of stationary contact devices to receive said terminals and connect the sheath in the electric circuit to be protected, ota spring plunger in the end of said sheath to give a signal, a fuse wireV within the sheath, means independent `of said fuse wire to normally retain the plunger in non-indicating position, the s ring serving to eject the plunger u on the b owing of the fuse to give a signa, substantially as de scribed.

5. In a protective appliance for electric circuits, the combination with a sheath, of a main fuse-wire therein connected in the circuit to be protected and carrying the principal portion ofsthe electric current, a

i. spring-pressed Signal to indicate when said fuse is lown, and an auxiliary fuse-member of small electric carryin capacity for normallyholding said -signa against operation and arranged to be severed by the blowing of the main fuse.

6. In a protectiveappliance for electric circuits, the combination with a sheath, of a fuse-wire therein connected in the circuit to be protected, a movable mechanical signal normally within said sheath and arranged to be projected beyond the same to indicate when the fuse is blown, and a member of holding said signal against operation., said member bein arranged to be severed by the blowing of a use.

. 7. In a protective appliance for electric circuits, the combination with a sheath, of a main fuse wire therein connected to carry the principal portion of the .electric current in the circuit to be protected, a mechanical signal, a spring to actuate said signal to indicate-when said fuse is blown, and an attenuated or thread-like memberfor normally holding said signal against operation and arranged to carry the current and be severed thereby when the fuse is blown, substantially as described.

8. In a protective appliance for electric circuits, the combination with a sheath, of a main fuse wire therein, connected in the circuit to be rotected to carry the princi al f portion of tlie electric'current, a slida le plunger, a spring to actuate said plunger to indicate when' the fuse. is blown, and an auxiliary member of small electric carrying capacity for normally holding saidv signal against operation and arrangedy to carry the current and 'be severed thereby when the .fuse is blown.

9. In a protective appliance for electric circuits, the combination with a sheath, of

small electric carrying capacity for normallyv a main fuse Wire therein connected in the circuit to be protected to carry the principal portion of the electric current, a mechanical signal having an indicating and a non-indicating position, means tending to move said signal to its indicating osition, and an auxiliary member of smal electric carrying capacity to hold said signal in non-indicating position, against the action of'said means, said auxiliary member being in the circuit and severed by the current when the fuse blows, whereby ysaid signal may move to its indicating'position.

10. In a protective appliance for electric circuits, the combination with a sheath, of

a main fuse Wire connected in the circuit to be protected to carry the principal ortion ofthe electriccurrent, a mechanica signall having an indicating and a non-indicating position, a spring tending to move said signa to its indicating position, and an auxiliary member of small electric carrying capacity to hold said signal in its non-indicating position against the tension of said spring, said auxiliary member being arranged in the circuit and severed by the current when the fuse blows, whereby said signal will bereleased.

11. In a protective device for electric circuits, the combination with a sheath, of a main fuse wire therein, connected in the circuit to be protected to carry the principal portion of the electric current, a mechanical signal also inclosed Within said sheath and adapted to be extended beyond said sheath, and a member of small electric carryin capacity for normally holding said signa against operation, which is arranged in the circuit and severed by the` current when the fuse blows.

12. 4In a protective 'appliance for electric circuits, the combination with a sheath, of a main fuse wire therein, connected in the circuit to be protected to carry the princi al portion of the electric current, a slida le signal associated with said sheath and having an indicating and non-indicating position, a spring tending to move said Signal to its indicating osition, and an auxiliary member of small electric carrying capacity to hold said signal .in its non-indicating position agalnst the tension of said spring, said -auxiliary member being connected in the circuit and severed by the current when the fuse blows,

'b whereby the signal will be .moved to its'indieating osition.

18. n a protective appliance for electric circuits, the combination with a sheath, of a main fuse wire therein, connected in the circuit to be protected to carry the principal portion of the electric current, a mechanical signal to indicate when said fuse is blown, and an auxiliary member of small electric carrying capacity for normally holding said signal against operation, said auxiliary member being suitably connected with the circuit in which said fuse is arranged, whereby when said fuse is blown, the current will traverse said auxiliar be disrupte should it not previously h ave been severed by the blowing of the fuse..

14.' In a protective a pliance for electric I circuits and apparatus, t e combination with an outer inclosing tube having suitable connections to include the same in theelectric circuit, of a removable fuse sheath within said inclosing tube, a-fuse wire within the sheath, and means for giving a signal exterior to the casing when the fuse wire is blown.

15. In a protective a pliance for electric circuits and apparatus, t ie combination with an outer tube or casing having suitable connections to include the same in the electric circuit, of ,a removable fuse-sheath within the casing, a fuse-wirewithin the sheath, and a mechanical signal exterior of said casing, and means whereby said signal is operated when the fuse-wire 1s blown.

16. In a protective a pliance for electric circuits and apparatus, t e combination with an outer casing having suitable connections -to include Athe s'ame in the electric circuit, of-

from said casing when the fuse is blown.

18. In a protective appliance for lelectric circuits and apparatus, t e combination with a casing having suitable connections to includethe same in the electric circuit, ofy a fuse sheath within the casing, a fuse wire within the sheath, a spring pressed signal, means to hold said signal against the tension of its spring, said means being connected in -the circuit to be disrupted bythe current when the fuse is blown, substantially as described. p

19. In a protective a pliance for electric circuits and apparatus, t e combination with a casing having a fuse sheath within said casing, of a fuse wire within said sheath, a spring pressed plunger within the casing having a part prolecting therefrom, and meansto restrain said plunger against the pressure of its member and cause the same to( Awhich is disrupted by the blowin an outer casing, of a fuse-sheath Within the casing, 'a main fuse-wire within the sheath,

a sup lemental or auxiliary attenuated or4 threa -like member arra d in said sheath,

circuits and apparatus t e combination with" and means controlled by said member for p' giving a signal when it is disrupted.

21. In a protective appliance for electric.

circuits and apparatus, t e combination with an outer, casing, of a fuse-sheath within the casing, a main fuse-wire within the sheath, n

a sup lemental. or auxiliary attenuated or threa -like member associated withl said wire and also disposed within the sheatl ailild o t e fuse-wire, and means controlled y said member for operating a signal upon the blowing of the wire.

22. In a protective a pliance.\for electric circuits andap aratus, t ecombination with a casing provi ed with an aperture, of afuse sheath within the casing having suitable connections to includethe same in the electric circuit, a fuse wire within the sheath, a' detachable part for said sheath, and means associated with said detachable part for prouse wire is blown, substantially as described.

. 23. In a protective a pliance for electric circuits and a aratus, t e combination with a casing provi ed with an aperture, of a fuse sheath within the casing, a fuse wire within the sheath, a spring pressed plunger carried by the sheath, arranged to operate and project a part of said sheath through the aperture in the casin when the fuse wire is blown, substantial y as described.

24. In a thermo electric cut out, in' combination with the main fuse wire, an auxiliary fuse wire of small electric carryin capacity, an indicator held confined b sai 'auxiliary conductor, a. spri adapte to project the indicatorupon the reaking of the auxiliary /HARRY HfHoRNsBY.

EDWARD w. ANGER, JR.u

' Witnesses:

M. R. Rocnroim,

ROBERT Liiwis Aims.

ecting it through said aperture when the 

